It is an essential condition to transmit a big volume of data at high speed in image processing, transmission media and telephone network. There is a need for several hundreds Mbps (mega bit per second) for mass storage of data at high speed and transmission speed at the rate of Tbps (tera bit per second) will be requested in the future.
Optical communication has been addressed as a solution for rapid processing of a huge volume of data. Particularly, wavelength division or frequency division multiplexing system utilizing parallellism of light of optical communication systems has been more in the spotlight than time division multiplexing system. Typical elements for optical communications include optical output splitter, wavelength division multiplexer, high speed optical modulator, switch, and so on. It is required that elements for optical waveguides have stabilities against optical loss, heat and humidity, polarization-dependent gain (PDG), easiness in processing and packaging, and so on. Silica has been widely used in the preparation of passive optical waveguides so far but studies in development using polymers containing hydrogen or fluoride have recently extensively increased.
Poly(arylene ether) is engineering plastic used widely in electronic materials and aerospace materials. Generally, fluorine-containing poly(arylene ether) or polyimide exhibits high thermal stability, chemical stability, low optical loss, low refractive index, low birefringence, low dielectric constant, easy processability, and low moisture absorption rate. It has been thus suitable for manufacturing elements used in information telecommunication field as well as use in thermoplastic polymer, membrane elastomer and so on. Especially, poly(arylene ether sulfide) (hereinafter referred to as ‘PAESIs’) has been introduced with a sulfur group for providing mechanical stability, thermal stability, resistance against fire, chemical stability, low birefringence, and low moisture absorption rate and an ether group for providing flexibility thereby providing superior advantage in manufacturing elements, while exhibiting similar properties of polyimides. Udel™ (poly ether sulfone), Kadel™ (poly ether ketone), PEEK™ [Poly (ether ether ketone)], and Victrex™ have been commercialized. Fluorinated poly(arylene ether sulfide) (hereinafter referred as to ‘FPAESIs’) has been in the spotlight because ether bond offers flexibility to the polymer main chain and kink structure of the polymer main chain. Thus, it provides high glass transition temperature due to correlation/canceling effect between irregular and regular structure. Aromatic nucleophilic substitution reaction (SNAr) is usually performed to prepare the FPAESIs, where monomers with dihydroxy functional group are used. A typical example of the dihydroxy monomer used in the preparation of FPAESIs is 4,4′-(hexafluoroisoproylidene)diphenol. Although other examples of fluorine-containing dihydroxy monomer include 9,9′-bis(4-hydroxyphenyl)fluorene, 2,2′,3,3′,5,5′6,6′-octafluoro-4,4′-biphenol hydrate, 4,4′-isopropylidenediphenol, 4,4′-(hexafluoroisoproylidene)diphenol, there are limited for FPAESIs.